The present invention relates to a driving assist device for a vehicle.
It is desired to warn a driver of any dangerous object existing around a vehicle from the safety aspect. Japanese Patent Laid-Open Publication No. 2001-1851 discloses an example of such an alarm device, in which sound images are positioned in the direction of dangerous objects, such as other vehicles or pedestrians, by using speakers (generating sounds) so that the driver can be warned of existence of the dangerous objects (i.e., sound fields are created so that the driver can hear alarm sounds from the exiting positions of the dangerous objects). Further, U.S. Pat. No. 7,274,288 discloses a device in which the position of a virtual sound source and the kind of alarm sounds are changed according to warning contents.
Herein, it is very preferable from the safety aspect that the driver recognize (judge) the distance of the dangerous object existing around from the vehicle. Accordingly, it may be considered that the alarm sound is created according to the distance of the dangerous object. For example, the sound volume (sound pressure) of the alarm sound may be set in such a manner that the alarm sound has a greater sound volume in case the object exists closer to the vehicle.
However, it may be difficult for the human to recognize (judge) the distance from it to a sound source simply by hearing the sound emitting from the sound source. That is, changing the sound volume of the alarm sound according to the distance may not be enough for the driver to precisely recognize the distance of the dangerous object from the vehicle.
Other publications, such as Japanese Patent Laid-Open Publication Nos. 5-126948 and 2007-312081, disclose different alarm devices. These devise, however, do not provide any effective countermeasures against the above-describe problem, either.